Hi, Bob - I'm going to give this a try:
A SLO (Service Level Objective) is an agreed upon service metric between the IT organization and one or more of its customer-communities, applied to the services provided to these communities.
KPIs (Key Performance Indicators) - are used to assess the performance of the processes (eg. Problem Mgmt, Change Mgmt) rather than the services.
Does that make sense?
/Sharon E.
(ps. SLO defn taken from HP)